<template>
  <div class="cart-box">
    <s-header :title="'购物车'"></s-header>
    <div class="cart-body">
      <van-checkbox-group @change="groupChange" v-model="result" ref="checkboxGroup">
        <van-swipe-cell :right-width="50" v-for="(item,index) in list" :key="index">
          <div class="good-item">
            <van-checkbox :name="item.cartItemId" />
            <div class="good-img"><img :src="`http://47.99.134.126:28019/${item.goodsCoverImg}`" alt=""></div>
            <div class="good-desc">
              <div class="good-title">
                <span>{{item.goodsName}}</span>
                <span>x{{item.goodsCount}}</span>
              </div>
              <div class="good-btn">
                <div class="price">￥{{item.sellingPrice}}</div>
                <van-stepper integer :min="1" :value="item.goodsCount" :name="item.cartItemId" async-change @change="onChange" />
              </div>
            </div>
          </div>
          <van-button slot="right" square icon="delete" type="danger" class="delete-button" @click="deleteGood(item.cartItemId)" />
        </van-swipe-cell>
      </van-checkbox-group>
    </div>
    <van-submit-bar v-if="list.length > 0" class="submit-all" :price="total * 100" button-text="结算" @submit="onSubmit" >
      <van-checkbox @click="allCheck" v-model="checkAll">全选</van-checkbox>
    </van-submit-bar>
    <div class="empty" v-if="!list.length">
      <van-icon name="smile-o" />
      <div class="title">购物车空空空如也</div>
      <van-button color="#1baeae" type="primary" @click="goTo" block>前往首页</van-button>
    </div>
  </div>
</template>

<script>
import sHeader from '@/components/SimpleHeader'
import { deleteCartItem, getCart, modifyCart } from '../service/cart'
import { Toast } from 'vant'
export default {
  name:'Cart',
  components:{
    sHeader
  },

  data() {
    return{
      list: [], //购物车商品列表
      result: [], //选中的购物车商品id数组
      checkAll: true
    }
  },

  mounted() {
    this.init()
  },

  methods: {
    //点击返回上一页
    goBack() {
      this.$router.go(-1)
    },
    //购物车为空时返回首页
    goTo() {
      this.$router.push({ path: 'home' })
    },
    async init() {
      // 加载中禁止点击
      Toast.loading({ message: '加载中...', forbidClick: true });
      // 获取购物车商品数据
      const { data } = await getCart({ pageNumber: 1 })
      this.list = data
      this.result = data.map(item => item.cartItemId)
      Toast.clear()
    },

    async deleteGood(id) {
      const { data } = await deleteCartItem(id)
      this.$store.dispatch('updateCart')
      this.init()
    },

    async onChange(value, detail) {
      if (this.list.filter(item => item.cartItemId == detail.name)[0].goodsCount == value) return
      Toast.loading({ message: '修改中...', forbidClick: true });
      const params = {
        cartItemId: detail.name,
        goodsCount: value
      }
      const { data } = await modifyCart(params)
      this.list.forEach(item => {
        if ( item.cartItemId == detail.name){
          item.goodsCount = value
        }
      })
      Toast.clear();
    },

    groupChange(result) {
      if (result.length == this.list.length) {
        this.checkAll = true
      } else {
        this.checkAll = false
      }
      this.result = result
    },

    async onSubmit() {
      const params = JSON.stringify(this.result)
      this.$router.push({ path: `create-order?cartItemIds=${params}`})
    },

    allCheck(value) {
       // 判断 checkAll ，如果已是全选状态，checkAll 将变为false，所以清空 result 内的变量，价格变为 0
      // 如果是非全选状态checkAll 将变为 true，直接将 list 下的 id 塞进 result 变量里，total 会自动变为相应的价格
      if (this.checkAll) {
        this.result = this.list.map(item => item.cartItemId)
      } else {
        this.result = []
      }
    }
  },
  
  computed:{
    total: function() {
      let sum = 0
      let _list = this.list.filter(item => this.result.includes(item.cartItemId))
      _list.forEach(item => {
        sum += item.goodsCount * item.sellingPrice
      })
      return sum
    }
  },

}
</script>

<style lang="less" scoped> 
  @import '../common/style/mixin.less';
  .cart-box {
    .cart-body {
      margin: 60px 0 100px 0;
      padding-left: 10px;
      .good-item {
        display: flex;
        .good-img {
          img {
            .wh(100px,100px)
          }
        }
        .good-desc {
          display: flex;
          flex-direction: column;
          justify-content: space-between;
          flex: 1;
          padding: 20px;
          .good-title {
            display: flex;
            justify-content: space-between;
          }
          .good-btn {
            display: flex;
            justify-content: space-between;
            .price {
              font-size: 16px;
              color: red;
              line-height: 28px;
            }
            .van-icon-delete {
              font-size: 20px;
              margin-top: 4px;
            }
          }
        }
      }
      .delete-button {
        width: 50px;
        height: 100%;
      }
    }
      .empty {
      width: 50%;
      margin: 0 auto;
      text-align: center;
      margin-top: 200px;
      .van-icon-smile-o {
        font-size: 50px;
      }
      .title {
        font-size: 16px;
        margin-bottom: 20px;
      }
    }
    .submit-all {
      margin-bottom: 50px;
      .van-checkbox {
        margin-left: 10px
      }
      .van-submit-bar__text {
        margin-right: 10px
      }
      .van-submit-bar__button {
        background: @primary;
      }
    }
  }
</style>

<style lang="less">
  @import '../common/style/mixin';
    .van-checkbox__icon--checked .van-icon {
    background-color: @primary;
    border-color: @primary;
  }
</style>